Structure characterization of films from drying oils cured under infrared light

Drying oils have been considered as water resistant coatings for bio‐based packaging materials; however, their curing rates are slow for industrial applications. Infrared radiation was investigated in this study as a means to increase the curing rate of linseed and tung oils. The effect of oil pretreatment with gamma radiation was also investigated. FTIR spectroscopy was used to monitor chemical changes during oil oxidation. Results indicated that infrared radiation increased the curing rate of linseed and tung oils. The oxidation rate of both oils, as monitored by the decrease of the 3010 cm^?1 FTIR peak, followed an exponential decay. The structure of cured films was examined by SEM. Images of films cross section were used to develop a qualitative model of the curing process. Linseed and tung oil showed differences in structural development during drying. In the case of linseed oil, the formation of a tough skin layer slowed down oxygen diffusion to the oil underneath, resulting in slow curing. For the case of tung oil, the skin layer shrank as it formed allowing oxygen diffusion and fast curing of tung oil. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Linseed oil on concrete: Penetration of linseed oil compositions into sheet-and liquid membrane-cured concretes

Penetrations of concrete specimens by solutions of boiled linseed oil in mineral spirits and emulsions of boiled linseed oil were measured. Concrete specimens were cured with polyethylene sheet (removable) and wax-based and resin-based compounds prior to penetration tests. Penetration was greatest at 35 days and least at four and seven days after curing. Penetration at 105 days was only slightly less at 35 days. Maximum penetrations were obtained with solutions more dilute than 50 volume per cent of linseed oil in mineral spirits. Penetrations on polyethylene-, wax- or resin-cured specimens varied from 1.5 to 3 mm when 50 volume per cent linseed oil solution or emulsion was spread on the specimen at the rate of 0.16 lb/yd². Presented before Committee MC-B4 at the Highway Research Board Meeting, Washington, D.C., January, 1970. No. Market. Nutr. Res. Div., ARS, USDA.     

Zu den Veränderungen von Rapsöl und Leinöl während der Verarbeitung

Changes of rapeseed and linseed oil during processing During processing of crude oil in a large oil mill, three samples each of rapeseed and linseed were investigated at each processing stage, i.e. press oil, solvent-extracted oil, mixed oil, and degummed/caustic refined oil. In the case of rapeseed also bleached and desodorized oils (230°C; 3.0 mbar for 2 h) were investigated. Rapeseed and linseed oil showing the typical major fatty acids contained less than 1% trans-isomeric fatty acids (trans fatty acids = TFA). Linseed oil had a similar TFA-concentration as rapeseed oil, and the concentrations did not change during the processing stages up to degummed/caustic refined oil, and were also unchanged in the bleached rapeseed oil. Desodorization of rapeseed oil, however, trebled the TFA concentration to 0.58%. The detected tocopherol patterns were typical of rapeseed and linseed oils. There was no difference between mixed oil and degummed/caustic refined oil in the total concentration of tocopherols. Neither had bleaching any effect. Rapeseed oil desodorization diminished total tocopherol concentration by 12% from 740 mg/kg to 650 mg/kg. Due to degumming/caustic refining the phosphorus concentration of both oils decreased to less than a tenth compared to mixed oil. Other elements determined in degummed/caustic refined rapeseed oil were not detectable (manganese < 0.02 mg/kg, iron < 0.4 mg/kg, copper < 0.02 mg/kg, lead < 10 μg/kg) or only as traces zink 0.1 mg/kg, cadmium 2 μg/kg). In linseed oil, which initially showed a higher trace compounds concentration, a significant decrease was found by degumming/caustic refining. Iron could not be detected. There were traces of zinc, manganese, copper, lead, and cadmium. There was no difference between the acid values of rapeseed and linseed crude oil. Acid value decreased drastically already during the degumming/caustic refining stage. The crude linseed oils had a higher peroxide value, anisidine value and diene value than the corresponding crude rapeseed oils. With peroxide values of ≤ 0.1 mEq O₂/kg found in almost all investigated rapeseed oils, no effect of refining could be detected. The anisidine value showed an increase after bleaching. Desodorization trebled the diene value.     

Corrosion aspects of alkyd paints modified with linseed and soy oils

The anticorrosive performance of medium-long (54-59%) alkyd paints modified with linseed and soy oils was compared by accelerated tests (Prohesion Cycle) and natural exposition in marine and industrial atmospheres. Differences on the protection mechanism of anticorrosive pigments due to substitution of linseed oil by soy oil were investigated by polarization curves and electrochemical impedance spectroscopy (EIS). Complementary tests such as water vapor and ions permeability in freestanding films were also performed. Results suggested that the type of oil influenced the barrier properties of the paint pigmented with zinc phosphate. The same tendency was verified by resistance values obtained from impedance diagrams. Polarization curves suggest that the action of the pigments in the alkyd paintings is practically the same for both oils. The substitution of linseed oil by soy oil did not impair the anticorrosive performance of alkyd paints and from the economic point of view this substitution could be very interesting.     

Synthesis and photopolymerization of norbornyl epoxidized linseed oil

Norbornyl epoxidized linseed oil was synthesized via Diels-Alder reaction of cyclopentadiene with linseed oil at high pressure (∼200 psi) and high temperature (240 °C), followed by an epoxidation using hydrogen peroxide with a quaternary ammonium tetrakis(diperoxotungsto) phosphate(3−) epoxidation catalyst. The products were characterized using ¹H and ¹³C NMR, FT-IR, and electrospray ionization mass spectroscopy. Photo-induced curing kinetics of norbornyl epoxidized linseed oil coatings was investigated using real-time FT-IR spectroscopy with a fiber optic UV-curing system. The norbornyl epoxidized linseed oil was formulated with three different divinyl ether reactive diluent. The effect of divinyl ether concentration and types of divinyl ether on the curing reaction was investigated. It was found that the curing rate of norbornyl epoxidized linseed oil was lower than that of cycloaliphatic epoxide, but higher than epoxidized linseed oil. The incorporation of divinyl ethers increased the curing rate and overall conversion of the epoxide groups. Of the three divinyl ethers used, coating with triethyleneglycol divinyl ether showed the highest curing rate and coating with cyclohexane dimethanol divinyl ether showed the lowest curing rate.     

Polyester networks based upon epoxidized and maleinated natural oils

Novel families of flexible, semiflexible and rigid crosslinked polyesters were prepared from modified natural oils such as soybean, rape-seed and linseed oil. Maleinated oils were used as anhydride-functional curing agents of epoxy resins such as bisphenol-A-diglycidylether and epoxidized natural oils. A new class of unsaturated polyester resins was based upon maleic anhydride, epoxidized natural oils and styrene. The resulting thermosetting polyesters were reinforced with natural fibers such as hemp and flax fibers. The influence of molecular architectures, curing conditions and formulations on thermal, mechanical and morphological properties were investigated.     

Studies on the properties of polyesters and polyester blends of selected vegetable oils

Melon‐seed and rubber‐seed oils have been used in the synthesis of polyester resins. Results reveal that rubber‐seed oil can completely be substituted for linseed and soyabean oils in the synthesis of both long and medium‐oil–length polyester resins. Melon‐seed oil was found to be a substitute for 50% of linseed oil and 50% of soyabean oil in the synthesis of long‐oil–length polyester resins. It also substituted for 15% of linseed oil and 50% of soyabean oil in the synthesis of medium‐oil–length polyester resins. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1441–1446, 2000     

Urethane coatings based on aldehyde oils

A series of polyol acetals of aldehyde oils was prepared by an acetal interchange reaction between dimethyl and tetramethyl acetals of aldehyde oils derived by the reductive ozonolysis of linseed and soybean oils. The acetals interchanged with pentaerythritol, trimethylol propane and glycerol contained the equivalent of .93 and 1.88 aldehyde groups per oil molecule. The polyol acetals were reacted with toluene diisocyanate in an NCO/OH of 2. These products were tested as film formers. Curing was by two reactions, namely oxidation polymerization of the residual unsaturation in the oil and moisture curing of the unreacted isocyanate group. Good quality films were formed. Presented at the AOCS-AACC Meeting, Washington, D.C., March, 1968.     

Partial hydrogenation of linseed oil by a continuous process

Summary Alkali refined linseed oil was partially hydrogenated, using both continuous and batch processes. The continuous process was carried out in a series of Votator machines, using Rufert nickel catalyst, presures up to 145 psig. and temperatures up to 400°F. The continuous hydrogenation of linseed oil under the most selective conditions possible, using the Votator equipment, shows little selectivity between the linolenic and linoleic acid radicals. A pronounced selectivity is observed between oleic and the more unsaturated acid radicals. Under selective conditions of hydrogenation of linseed oil about 31% of the hydrogenated linolenic acid radical is transformed into 9–15 linoleic acid while the remainder of the linolenic acid goes to oleic acid in either one or two steps. Batch hydrogenation yields oils of superior nonyellowing characteristics over comparable oils prepared by the continuous process. The hydrogenated linseed oils were tested in both clear and pigmented alkyds where they displayed superior non-yellowing characteristics over the original linseed oil and, in many instances, over that of soya bean oil. The yellowing of oils and alkyds appears to be a function of both 1) the quantity of fatty acids more unsaturated than oleic present in the oil and 2) the ratio of the quantity of linolenic acid radicals to linoleic acid radicals present. Presented at 21st fall meeting, American Oil Chemists' Society, Chicago, Oct. 20–22, 1947.     

Polymerization of linseed oil in an electric discharge

Summary The treatment of linseed oil by the action of electric discharges (voltolization) in a hydrogen atmosphere (80 mm. Hg, 70°C.) is described. It has been known for a long time that voltolization of linseed oil brings about a polymerization of the oil. Now it has been proven that the nature of the polymerization product thus obtained is absolutely different from that of thermally or catalytically polymerized linseed oils. In contrast to the latter, voltolized linseed oils contain only small amounts of cyclic compounds. Their viscosity is relatively low, even at a high polymerization degree, and considerably less than that of thermally polymerized oils of a corresponding degree of polymerization. Atomic hydrogen seems to play an important part in the voltolization process. Coupling of fatty acid chains is made possible by combining radicals, formed primarily by the action of hydrogen atoms. Coupling reaction occurs almost exclusively intermolecularly. The possibility of transforming linseed oil and other drying oils into polymerization products of a completely different chemical structure, depending on the applied polymerization process, opens new possibilities for their manufacture. Compare T. Hoekstra, Thesis, Delft 1958 (in Dutch).     

Fracture toughness and impact strength of anhydride‐cured biobased epoxy

Biobased neat epoxy materials containing functionalized vegetable oils (FVO), such as epoxidized linseed oil (ELO) and epoxidized soybean oil (ESO), were processed with an anhydride curing agent. A percentage of diglycidyl ether of bisphenol F (DGEBF) was replaced by ELO or ESO. The selection of the DGEBF, FVO, and an anhydride‐curing agent resulted in an excellent combination to produce a new biobased epoxy material having a high elastic modulus and high glass transition temperature. Izod impact strength and fracture toughness were significantly improved dependent on FVO content, which produced a phase‐separated morphology. POLYM. ENG. SCI., 45:487–495, 2005. © 2005 Society of Plastics Engineers     

Studies on the alcoholysis of some seed oils

The effects of time and temperature on the alcoholysis of rubber seed, melon seed, linseed, and soyabean oils have been studied. The following temperatures were investigated: 200, 220, 245, and 260°C. Litharge (PbO) was used as the alcoholysis catalyst. The optimum alcoholysis temperature was found to be 245 ± 2 °C for each of the oils. At lower alcoholysis temperatures (<245°C), there is the preferential alcoholysis of seed oils derived from unsaturated acid; and the general alcoholysis rates were found to be in the following order: linseed oil ≈ rubber seed oil ≥ soyabean oil ≈ melon seed oil. The alcohol‐solubility of the oils is generally observed to begin at 42–45% conversion of oils to monoglycerides. The α‐monoglyceride contents of the alcoholysis mixtures of rubber seed and linseed oils were generally similar at methanol tolerance, and higher than those of melon seed and soyabean oils. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1826–1832, 2000     

Heat treatment of vegetable oils. II. GC-MS and GC-FTIR spectra of some isolated cyclic fatty acid monomers

Gas liquid chromatography coupled with mass spectrometry (GC-MS) showed that the cyclic fatty acid monomers (CFAM) isolated from a heated linseed oil have two ethylenic bonds, while the CFAM isolated from heated sunflower oils were saturated and monoethylenic isomers. GC-MS studies also showed the presence of cyclohexenic derivatives in the case of linseed oil. GLC coupled with Fourier transform infrared spectrometry (GC-FTIR) studies indicated that the CFAM isolated from linseed oil were ofcis (Z),trans (E) structures except two components which werecis,cis (Z,Z) dienoic acids. The unsaturated CFAM isolated from sunflower oils werecis (Z) andtrans (E) monoethylenic isomers. For sunflower oils, the major CFAM were isomers having acis (Z) ethylenic bond. The saturated CFAM isolated from a heated sunflower oil had molecular weights of 296 and 294. The latter could correspond to some bicyclic isomers.     

Formation of trans isomers during the hydrogenation of glyceride oils

Summary Conditions which favor the selective hydrogenation of glyceride oils also favor the development of trans isomers. Complete curves are presented showing the formation and disappearance of trans isomers during the hydrogenation of linseed oil, soybean oil, cottonseed oil, olive oil, lard, and edible tallow, as determined by the infrared spectrophotometric method. An unusually high percentage of tran linkages develops during the hydrogenation of tallow.     

Chemical composition and physicochemical and hydrogenation characteristics of high-palmitic acid solin (low-linolenic acid flaxseed) oil

The physicochemical characteristics and FA compositions were determined for refined-bleached-deodorized (RBD) high-palmitic acid solin (HPS) oil, RBD solin oil, and degummed linseed oil. The predominant FA in HPS oil were palmitic (16.6%), palmitoleic (1.4%), stearic (2.5%), oleic (11.3%), linoleic (63.7%), and linolenic (3.4%). HPS oil was substantially higher in palmitic acid than either solin oil or linseed oil, and similar to solin oil in linolenic acid content. HPS, solin, and linseed oils exhibited similar sterol and tocopherol profiles. The physicochemical characteristics of the three oils (iodine value, saponification value, m.p., density, specific gravity, viscosity, PV, FFA content, color) reflected their FA profiles and degree of refinement. During hydrogenation of HPS oil, the proportion of saturated FA (palmitic and stearic) increased, and that of unsaturated FA (oleic, linoleic, and linolenic) decreased as the iodine value declined. This resulted in an inverse linear relationship between m.p. and iodine value. Hydrogenation also generated trans FA. The proportion of trans FA was inversely related to iodine value in partially hydrogenated samples. Fully hydrogenated HPS oil (i.e., HPS stearine, iodine value <5) was devoid of trans FA.     

Bitter off‐taste in stored cold‐pressed linseed oil obtained from different varieties

Freshly pressed linseed oil shows a delicate nutty flavor. However, after only 1 day of storage, a bitter off‐taste develops. It is caused mainly by the formation of a cyclic octa‐peptide named cyclolinopeptide E (CLE) containing the oxidized amino acid methionine. A simple and fast determination by solid‐phase extraction and high‐performance liquid chromatography with UV detection has been developed in order to measure the formation of this cyclic peptide during storage in correlation with the increasing bitter off‐taste of the oil, which was determined by a sensory panel. The development of this bitter off‐taste was analyzed in several oils prepared from linseed of a single variety from seeds obtained during a growing test. Highest bitterness was perceived in oil from the variety Eurodor, corresponding to CLE contents of 925 mg/kg, and lowest bitterness was perceived in oil from the variety Baladin, corresponding to a CLE content of 485 mg/kg. In some varieties, additional bitter compounds might be present in significant amounts.     

Copper-hydrogenated soybean and linseed oils: Composition,organoleptic quality and oxidative stability

Copper and nickel hydrogenations give a wide distribution of double bonds in the monoene fraction from both reduced soybean and linseed oils. With copper catalysts, high pressure hydrogenation reduces the extent of this double bond distribution when compared with low pressure hydrogenation. With nickel catalysts, some Δ17-octadecenoate is formed but less than with a copper catalyst. In room odor evaluations, copper-hydrogenated soybean (CuHSB) oil gave higher scores and lower fishy responses than nickel-hydrogenated soybean oil after both had been exposed to fluorescent light. A mixture of CuHSB oil (33%) and peanut oil received room odor scores equal to or better than peanut oil alone, whether light exposed or not. Although hydrogenated products with remarkable stability to oxidation were obtained by copper hydrogenation of linseed oil, these oils have lower organoleptic stability when compared to nickel-hydrogenated, winterized soybean oil.     

Some aspects of the fluorescence of drying oils

Summary The fluorescence of vegetable oils may arise from both the non-glyceride and the glyceride components of the oil. When linseed and safflower oils are heated, fluorescence decreases at first and then increases as polymerization progresses. The fluorescence of heated vegetable oils is masked by decomposition products and by nitromethane. Relating fluorescence to other characteristics of heated oils shows different functional relations for linseed, safflower, tung, and oiticica oils, and a general similarity of behavior between the two non-conjugated oils and also between the conjugated oils. Contribution from the Division of Applied Biology. Issued as N.R.C. No. 3618.     

Synthetic oils from residual dimerized fat acids

Summary Synthetic oils have been prepared from residual dimerized fat acids with soybean and linseed fat acids by esterification with polyalcohols, and with or without maleic anhydride or phthalic anhydride. Preliminary evaluation indicates that these oils give films which dry faster and are more resistant to water and alkali than linseed oil films. This enhancement of water and alkali resistance may result from an increase in C-C bonds present in the films. Ester gum varnishes made from these oils were not markedly superior to similar varnishes made from linseed oil. The Northern Regional Research Laboratory is one of four Regional Laboratories authorized by Congress in the Agricultural Research Act of 1938 for the purpose of conducting research to develop new uses and outlets for agricultural commodities. These Laboratories are administered and operated by the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.